    /**
     * @docauthor Jason Johnston <jason@sencha.com>
     *
     * A file upload field which has custom styling and allows control over the button text and other
     * features of {@link Ext.form.field.Text text fields} like {@link Ext.form.field.Text#emptyText empty text}.
     * It uses a hidden file input element behind the scenes to allow user selection of a file and to
     * perform the actual upload during {@link Ext.form.Basic#submit form submit}.
     *
     * Because there is no secure cross-browser way to programmatically set the value of a file input,
     * the standard Field `setValue` method is not implemented. The `{@link #getValue}` method will return
     * a value that is browser-dependent; some have just the file name, some have a full path, some use
     * a fake path.
     *
     * **IMPORTANT:** File uploads are not performed using normal 'Ajax' techniques; see the description for
     * {@link Ext.form.Basic#hasUpload} for details.
     *
     * # Example Usage
     *
     *     @example
     *     Ext.create('Ext.form.Panel', {
     *         title: 'Upload a Photo',
     *         width: 400,
     *         bodyPadding: 10,
     *         frame: true,
     *         renderTo: Ext.getBody(),
     *         items: [{
     *             xtype: 'filefield',
     *             name: 'photo',
     *             fieldLabel: 'Photo',
     *             labelWidth: 50,
     *             msgTarget: 'side',
     *             allowBlank: false,
     *             anchor: '100%',
     *             buttonText: 'Select Photo...'
     *         }],
     *
     *         buttons: [{
     *             text: 'Upload',
     *             handler: function() {
     *                 var form = this.up('form').getForm();
     *                 if(form.isValid()){
     *                     form.submit({
     *                         url: 'photo-upload.php',
     *                         waitMsg: 'Uploading your photo...',
     *                         success: function(fp, o) {
     *                             Ext.Msg.alert('Success', 'Your photo "' + o.result.file + '" has been uploaded.');
     *                         }
     *                     });
     *                 }
     *             }
     *         }]
     *     });
     */
    Ext.define("Ext.form.field.File", {
        extend: 'Ext.form.field.Trigger',
        alias: ['widget.filefield', 'widget.fileuploadfield'],
        alternateClassName: ['Ext.form.FileUploadField', 'Ext.ux.form.FileUploadField', 'Ext.form.File'],
        uses: ['Ext.button.Button', 'Ext.layout.component.field.Field'],

        /**
         * @cfg {String} buttonText
         * The button text to display on the upload button. Note that if you supply a value for
         * {@link #buttonConfig}, the buttonConfig.text value will be used instead if available.
         */
        //<locale>
        buttonText: 'Browse...',
        //</locale>

        /**
         * @cfg {Boolean} buttonOnly
         * True to display the file upload field as a button with no visible text field. If true, all
         * inherited Text members will still be available.
         */
        buttonOnly: false,

        /**
         * @cfg {Number} buttonMargin
         * The number of pixels of space reserved between the button and the text field. Note that this only
         * applies if {@link #buttonOnly} = false.
         */
        buttonMargin: 3,

        /**
         * @cfg {Object} buttonConfig
         * A standard {@link Ext.button.Button} config object.
         */

        /**
         * @event change
         * Fires when the underlying file input field's value has changed from the user selecting a new file from the system
         * file selection dialog.
         * @param {Ext.ux.form.FileUploadField} this
         * @param {String} value The file value returned by the underlying file input field
         */

        /**
         * @property {Ext.Element} fileInputEl
         * A reference to the invisible file input element created for this upload field. Only populated after this
         * component is rendered.
         */

        /**
         * @property {Ext.button.Button} button
         * A reference to the trigger Button component created for this upload field. Only populated after this component is
         * rendered.
         */

        /**
         * @cfg {String} [fieldBodyCls='x-form-file-wrap']
         * An extra CSS class to be applied to the body content element in addition to {@link #fieldBodyCls}.
         */
        fieldBodyCls: Ext.baseCSSPrefix + 'form-file-wrap',

        /**
         * @cfg {Boolean} readOnly
         * Unlike with other form fields, the readOnly config defaults to true in File field.
         */
        readOnly: true,

        // private
        componentLayout: 'triggerfield',

        // private. Extract the file element, button outer element, and button active element.
        childEls: ['fileInputEl', 'buttonEl', 'buttonEl-btnEl', 'browseButtonWrap'],

        // private
        onRender: function() {
            var me = this,
                inputEl;

            me.callParent(arguments);

            inputEl = me.inputEl;
            inputEl.dom.name = ''; //name goes on the fileInput, not the text input

            me.fileInputEl.dom.name = me.getName();
            me.fileInputEl.on({
                scope: me,
                change: me.onFileChange
            });

            if (me.buttonOnly) {
                me.inputCell.setDisplayed(false);
            }

            // Ensure the trigger cell is sized correctly upon render
            me.browseButtonWrap.dom.style.width = (me.browseButtonWrap.dom.lastChild.offsetWidth + me.buttonEl.getMargin('lr')) + 'px';
            if (Ext.isIE) {
                me.buttonEl.repaint();
            }
        },

        /**
         * Gets the markup to be inserted into the subTplMarkup.
         */
        getTriggerMarkup: function() {
            var me = this,
                result,
                btn = Ext.widget('button', Ext.apply({
                    id: me.id + '-buttonEl',
                    ui: me.ui,
                    disabled: me.disabled,
                    text: me.buttonText,
                    cls: Ext.baseCSSPrefix + 'form-file-btn',
                    preventDefault: false,
                    style: me.buttonOnly ? '' : 'margin-left:' + me.buttonMargin + 'px'
                }, me.buttonConfig)),
                btnCfg = btn.getRenderTree(),
                inputElCfg = {
                    id: me.id + '-fileInputEl',
                    cls: Ext.baseCSSPrefix + 'form-file-input',
                    tag: 'input',
                    type: 'file',
                    size: 1
                };
            if (me.disabled) {
                inputElCfg.disabled = true;
            }
            btnCfg.cn = inputElCfg;
            result = '<td id="' + me.id + '-browseButtonWrap">' + Ext.DomHelper.markup(btnCfg) + '</td>';
            btn.destroy();
            return result;
        },

        /**
         * @private
         * Creates the file input element. It is inserted into the trigger button component, made
         * invisible, and floated on top of the button's other content so that it will receive the
         * button's clicks.
         */
        createFileInput : function() {
            var me = this;
            me.fileInputEl = me.buttonEl.createChild({
                name: me.getName(),
                id: me.id + '-fileInputEl',
                cls: Ext.baseCSSPrefix + 'form-file-input',
                tag: 'input',
                type: 'file',
                size: 1
            });
            me.fileInputEl.on({
                scope: me,
                change: me.onFileChange
            });
        },

        /**
         * @private Event handler fired when the user selects a file.
         */
        onFileChange: function() {
            this.lastValue = null; // force change event to get fired even if the user selects a file with the same name
            Ext.form.field.File.superclass.setValue.call(this, this.fileInputEl.dom.value);
        },

        /**
         * Overridden to do nothing
         * @method
         */
        setValue: Ext.emptyFn,

        reset : function(){
            var me = this;
            if (me.rendered) {
                me.fileInputEl.remove();
                me.createFileInput();
                me.inputEl.dom.value = '';
            }
            me.callParent();
        },

        onDisable: function(){
            this.callParent();
            this.disableItems();
        },

        disableItems: function(){
            var file = this.fileInputEl;
            if (file) {
                file.dom.disabled = true;
            }
            this['buttonEl-btnEl'].dom.disabled = true;
        },

        onEnable: function(){
            var me = this;
            me.callParent();
            me.fileInputEl.dom.disabled = false;
            this['buttonEl-btnEl'].dom.disabled = true;
        },

        isFileUpload: function() {
            return true;
        },

        extractFileInput: function() {
            var fileInput = this.fileInputEl.dom;
            this.reset();
            return fileInput;
        },

        onDestroy: function(){
            Ext.destroyMembers(this, 'fileInputEl', 'buttonEl');
            this.callParent();
        }
    });